Add opportunistic_maintenance_strategy to GKE node_config host_maintenance_policy

[DrFaust92]

Adds the beta-only opportunistic_maintenance_strategy block under node_config.host_maintenance_policy, shared by google_container_cluster and google_container_node_pool. This exposes GKE's opportunistic maintenance feature — the Terraform equivalent of the gcloud container node-pools create --opportunistic-maintenance flag.

Fields (all beta, ForceNew):

• node_idle_time_window — idle time before maintenance is triggered
• maintenance_availability_window — window in which opportunistic maintenance may run
• min_nodes_per_pool — minimum available nodes; blocks maintenance below this

Maps to the API's HostMaintenancePolicy.opportunisticMaintenanceStrategy (container/v1beta1), which is absent from GA — so it sits under the existing beta guard on host_maintenance_policy. min_nodes_per_pool uses ForceSendFields so an explicit 0 is sent rather than dropped by omitempty.

Also documents host_maintenance_policy in the cluster docs (it was previously undocumented).

Testing

Verified end-to-end against a real GKE project:

• CPU node pool → API returns 400: opportunistic maintenance strategy is supported with TPU or GPU node pools only, confirming the field is parsed and validated by the API.
• GPU (nvidia-tesla-t4) node pool → the full config is accepted by the API.

Because opportunistic maintenance requires a GPU/TPU node pool and a host-maintenance allowlist, TestAccContainerNodePool_withOpportunisticMaintenance is t.Skip'd by default (consistent with the existing TestAccContainerNodePool_withHostMaintenancePolicy) and intended to be run manually in an allowlisted project with GPU capacity.

Note for maintainers

host_maintenance_policy is beta-only (absent from the GA container/v1 API and Go client), but its schema block is currently not beta-guarded — only its expand/flatten wiring is. So the field (and now opportunistic_maintenance_strategy) appears in the GA provider schema while being inert there. This is pre-existing behavior — maintenance_interval already does this — and I followed the existing pattern rather than change it in this PR. Happy to additionally wrap the whole host_maintenance_policy schema block in the beta guard if you'd prefer to fix the leak (note that would remove the field from the GA schema, a minor breaking change for any GA config that references it).

container: added `opportunistic_maintenance_strategy` to `host_maintenance_policy` in `node_config` for `google_container_cluster` and `google_container_node_pool` (beta)

[github-actions]

Googlers: For automatic test runs see go/terraform-auto-test-runs.

@c2thorn, a repository maintainer, has been assigned to review your changes. If you have not received review feedback within 2 business days, please leave a comment on this PR asking them to take a look.

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[c2thorn]

I'd rather beta-guard the field, similar to ephemeral_storage_config, although I acknowledge the other field not doing so.

No need to make a larger breaking change, let's just not introduce this specific field to GA.

[DrFaust92]

Done — beta-guarded opportunistic_maintenance_strategy so it's not introduced to GA (schema + the cluster/node-pool meta.yaml entries), matching the ephemeral_storage_config pattern. The expand/flatten paths were already inside the beta-only host_maintenance_policy helpers. Left the existing maintenance_interval/host_maintenance_policy GA exposure alone as you noted.

Verified locally via mmv1 generation: GA renders 0 opportunistic_maintenance_strategy occurrences (schema, meta.yaml, and the acceptance test all excluded), beta unchanged.

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes for commit 8066006:

Diff report

Your PR generated the following diffs in downstream repositories:

Repository	Diff Link	Changes
google provider	View Diff	1 file changed, 16 insertions(+)
google-beta provider	View Diff	5 files changed, 194 insertions(+), 1 deletion(-)
terraform-google-conversion	View Diff	1 file changed, 3 insertions(+)

Missing test report

Your PR includes resource fields which are not covered by any test.

Resource: google_container_cluster (602 total tests)
Please add an acceptance test which includes these fields. The test should include the following:

resource "google_container_cluster" "primary" {
  node_config {
    host_maintenance_policy {
      opportunistic_maintenance_strategy {
        maintenance_availability_window = # value needed
        min_nodes_per_pool              = # value needed
        node_idle_time_window           = # value needed
      }
    }
  }
  node_pool {
    node_config {
      host_maintenance_policy {
        opportunistic_maintenance_strategy {
          maintenance_availability_window = # value needed
          min_nodes_per_pool              = # value needed
          node_idle_time_window           = # value needed
        }
      }
    }
  }
}

Missing doc report (experimental)

The following resources have fields missing in documents.

• google_container_cluster
  • Expected Document Path: /website/docs/r/container_cluster.html.markdown
  • Fields: [node_pool.node_config.host_maintenance_policy.opportunistic_maintenance_strategy node_pool.node_config.host_maintenance_policy.opportunistic_maintenance_strategy.maintenance_availability_window node_pool.node_config.host_maintenance_policy.opportunistic_maintenance_strategy.min_nodes_per_pool node_pool.node_config.host_maintenance_policy.opportunistic_maintenance_strategy.node_idle_time_window]
• google_container_node_pool
  • Expected Document Path: /website/docs/r/container_node_pool.html.markdown
  • Fields: [node_config.host_maintenance_policy.opportunistic_maintenance_strategy node_config.host_maintenance_policy.opportunistic_maintenance_strategy.maintenance_availability_window node_config.host_maintenance_policy.opportunistic_maintenance_strategy.min_nodes_per_pool node_config.host_maintenance_policy.opportunistic_maintenance_strategy.node_idle_time_window]

Test report

Important

Manual Verification Required

VCR cannot automatically execute the following tests added in this PR. Please verify them manually:

🔴 TestAccContainerNodePool_withOpportunisticMaintenance

Analytics

Total Tests	Passed	Skipped	Affected
321	305	16	0

Affected Service Packages

• container

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🔴 Manual Verification Required: New tests were added that are skipped in presubmit tests. See the "Manual Verification Required" section at the top for details.

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[github-actions]

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